<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    * {
      margin: 0;
      padding: 0;
    }
    .box {
      position: relative;
      top: 30px;
      left: 50%;
      margin-left: -222px;
      width: 444px;
      height: 320px;
    }
    .box img {
      width: 100%;
      height: 100%;
    }

    .box::before {
      content: "";
      display: none;
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, .4) url(./images/arr.png) no-repeat center;
      
    }

    .box:hover::before {
      display: block;
    }

  </style>
</head>
<body>
  <div class="box">
    <div class="mask"></div>
    <img src="./images/tudou.jpg" alt="">
  </div>
</body>
</html>